The present invention relates to a diagnostic tool that allows for retroactive assessment of an industrial process via simulation of the industrial process using historical data acquired in real-time during performance of the industrial process.
Industrial controllers are special purpose computers used for controlling industrial processes and manufacturing equipment on a real-time basis. Under the direction of a stored program, the industrial controller examines a set of inputs reflecting the status of the controlled process and changes a set of outputs controlling the industrial process. During the industrial process, those inputs and outputs can be graphically displayed using a human machine interface (HMI) in the form of process animation, ladder logic, data values, or similar construct to provide real-time or “live” monitoring of the industrial process. Moreover, an operator, such as a process engineer, may then perform any diagnostic or debugging assessments on this “live” data.
Conventional HMI's are designed to process real-time values that are input thereto by the industrial controller. In order for a process engineer to assess the industrial process using the monitoring tools provided by the HMI, such as ladder logic and process animation, functional block diagrams, and sequential function charts, simulated data values for the industrial process must be created using a model of the industrial process and input to the HMI for processing. To debug the industrial process, or portion thereof, the process engineer must either debug a simulation of the industrial process or manually create values that are believed to be consistent with those provided during the industrial process. However, this modeled data may not reveal the problem with the actual industrial process which may deviate from the idealized model.
In contrast, historian services have been implemented in industrial control applications to acquire time-series data during cycles of the industrial process for retroactive analysis. Generally, historian services collect and store the data that is fed to the HMI. The data is stored in a database that arranges the data based on the time at which it was acquired. This time-ordered data thereby provides a historical perspective of the industrial process that can be used to generate trending reports, charts, graphs, and the like that may be viewed on devices like an HMI, engineering workstation, IT computer, and similar devices.